Li Zhen-Zhen, Zhang Li, Li Si, Dong He, Wang Qiao-Yan, Liu Xi-Ping, Yao Ya-Qin
Ying Yong Sheng Tai Xue Bao. 2014 Oct;25(10):2944-50.
Seedlings of the popular maize cultivar "Zhengdan-958" growing in pots individually were exposed to suitable soil water conditions as control, light water shortage, moderate water shortage, and severe water shortage, corresponding to soil water contents between 75%-85%, 65%-75%, 55%-65%, and 45%-55% of field water capacity, respectively. Responses of stomatal aperture, Kranz anatomy, and vascular bundle structure to different water contents of maize leaves were investigated. Results showed that under increased water shortages, the levels of H2O2 in both guard cells and subsidiary cells were enhanced, also the fluorescence intensity of H2O2 labeled with fluorescent dye increased, while stomatal aperture and conductance decreased gradually. Moreover, Kranz cells were messily arranged and the cell size became smaller and smaller, and the structure of bundle sheath cells went irregular; and the sectional area of the big bundle and xylem, the cell number of phloem, and the thickness of whole leaf and of upper and lower epidermis reduced. In addition, the number of chloroplasts in mesophyll cells and vascular bundle sheath cells decreased, particularly under the moderate water deficit, chloroplasts in Kranz cells which located in the inside of cytoplasmic membrane and cling on the cell wall spread to the direction of cell center. It demonstrated that stomatal closing of maize could be regulated by H2O2 in guard cells and subsidiary cells together, and H2O2 in subsidiary cells maybe played a cooperative role. In conclusion, under increased soil water shortages, drought-induced H2O2 accumulations in both guard cells and subsidiary cells of maize leaves participated in the regulation of stomatal closing. And, the size of Kranz cells and bundle sheath cells, the cell number of phloem, and the area of the xylem and phloem re- duced, thereby, reducing water shortage-induced damage.
将单个种植在花盆中的 popular 玉米品种“郑单 958”幼苗分别置于适宜土壤水分条件（对照）、轻度缺水、中度缺水和重度缺水环境下，对应土壤含水量分别为田间持水量的 75%-85%、65%-75%、55%-65%和 45%-55%。研究了玉米叶片气孔孔径、花环结构和维管束结构对不同水分含量的响应。结果表明，随着缺水程度增加，保卫细胞和副卫细胞中 H2O2 水平升高，用荧光染料标记的 H2O2 荧光强度也增加，而气孔孔径和导度逐渐降低。此外，花环细胞排列紊乱，细胞尺寸越来越小，维管束鞘细胞结构不规则；大维管束和木质部的横截面积、韧皮部细胞数量以及全叶和上下表皮厚度减小。另外，叶肉细胞和维管束鞘细胞中叶绿体数量减少，特别是在中度水分亏缺条件下，位于质膜内侧并紧贴细胞壁的花环细胞中的叶绿体向细胞中心方向扩散。这表明玉米气孔关闭可能由保卫细胞和副卫细胞中的 H2O2 共同调节，副卫细胞中的 H2O2 可能起协同作用。总之，在土壤缺水程度增加时，干旱诱导玉米叶片保卫细胞和副卫细胞中 H2O2 积累参与气孔关闭调节。并且，花环细胞和维管束鞘细胞大小、韧皮部细胞数量以及木质部和韧皮部面积减小，从而减轻缺水诱导的损伤。
